1. Field of the Invention
The present invention relates to an unwrapping apparatus for unwrapping a package wrapped with a wrapping sheet to obtain a solid object wrapped therein.
2. Description of the Related Art
Heretofore, there has been a widely used dry-type slide for chemical analysis (hereinafter, referred to simply as a xe2x80x9cslidexe2x80x9d). Such a slide may be used for quantitative analysis of a chemical component or a material component of a liquid sample dripped thereon. More specifically, the quantitative analysis may be carried out by dripping a drop of the liquid sample on the slide, putting the slide in an incubator for a predetermined time to promote color reaction (i.e., color matter producing reaction) of the liquid sample, irradiating the slide with radiation including a predetermined wavelength to measure optical density of a target biochemical substance contained in the liquid sample, and determining physical density of the target biochemical substance based on the measured optical density referring to a predetermined working curve correlating the optical density of the biochemical substance with the physical density thereof. The predetermined wavelength included in the radiation is determined depending on the combination of the target biochemical substance contained in the liquid sample and a reagent mixed in a material of the slide. The entire process described above is carried out by a suitably configured biochemical analyzer.
The biochemical analyzer used for the above quantitative analysis has a slide stocking portion which holds a plurality of slides ready for the analysis. Usually, when shipping the slides, each slide is wrapped tightly with a plastic film laminated with a metal lamina or a plurality of slides are packed in a single tightly-wrapped cartridge. In each case, an unwrapped slide must be used immediately or stocked in a dry atmosphere, as the reagent mixed in the material of the slide deteriorates rapidly. Therefore, it is desirable to use a plurality of individually-wrapped slides when there is a need to analyze many slides. However, in such a case, preparation for the analysis will require a lot of effort if the examiner has to manually unwrap each slide.
To reduce the problem, there have been several known apparatuses for unwrapping a package wrapped with a wrapping sheet such as a wrapping film to obtain a solid object wrapped therein. One example of such apparatuses is disclosed in Japanese Unexamined Patent Publication No. 9(1997)-237383. The apparatus disclosed in the Publication is directed to unwrapping a belt-like package containing a series of sub-packs each containing beverage ingredients therein. The sub-packs are tightly sandwiched between an upper wrapping sheet and a lower wrapping sheet. Although the disclosed apparatus is capable of unwrapping the belt-like package by peeling off the upper wrapping sheet from the lower wrapping sheet to obtain the sub-packs therein, the examiner is still required to manually detach edges of the upper and lower wrapping sheets in advance. Thus, the disclosed apparatus is incapable of unwrapping the individually wrapped slides.
An object of the present invention is to provide an unwrapping apparatus capable of automatically unwrapping a package containing a solid object such as the slide described above wrapped with a wrapping sheet.
According to the first aspect of the present invention, there is provided an unwrapping apparatus for unwrapping a package containing a solid object tightly wrapped with a wrapping sheet, the package including an unsealed space where the solid object is contained and a sealed portion surrounding the unsealed space, comprising: paired rollers rotatable so that the package caught between the paired rollers is transferred along a predetermined transferring path; a cutter located behind the paired rollers along the transferring path for making a slit on the unsealed space at a position near the front edge of the package; and controlling means for controlling operations of the paired rollers and the cutter by setting nip pressure applied to the package by the paired rollers at a pressure suitable both for transferring the package containing the solid object and for transferring the wrapping sheet without the solid object, rotating the paired rollers in respective predetermined directions so that the package is forwarded along the predetermined transferring path, terminating rotation of the paired rollers when the rear edge of the package comes between the paired rollers, making a slit on the package, and rotating the paired rollers in the directions opposite to the predetermined directions so that only the wrapping sheet separated from the solid object is transferred back by the paired rollers.
When using the above unwrapping apparatus according to the first aspect of the present invention, the rotation of the paired rollers is terminated when the rear edge of the package comes between the paired rollers after the paired rollers have run on a portion of the package where the solid object resides. Then, the paired rollers are rotated in the opposite directions after the slit is formed on the package. Now, the solid object within the package cannot be held between the paired rollers and thus cannot be transferred backward. Thus, only the wrapping sheet is transferred back to the area in front of the paired rollers. Therefore, the solid object within the package is gradually squeezed out from the slit formed on the package, and the solid object is separated from the wrapping sheet. That is to say, the unwrapping apparatus according to the first aspect of the present invention automatically unwraps the package to separate the solid object therein from the wrapping sheet. In addition, as the wrapping sheet separated from the solid object is pressed between the paired rollers while being transferred backward, the bulk of the removed wrapping sheet is reduced to facilitate handling thereof.
According to the second aspect of the present invention, there is provided an unwrapping apparatus for unwrapping a package containing a solid object tightly wrapped with a wrapping sheet, the package including an unsealed space where the solid object is contained and a sealed portion surrounding the unsealed space, comprising: paired rollers rotatable so that the package caught between the paired rollers is transferred along a predetermined transferring path; nip pressure altering means for altering nip pressure applied to the package by the paired rollers; a cutter located behind the paired rollers along the transferring path for making a slit on the unsealed space at a position near the front edge of the package; and controlling means for controlling operations of the paired rollers, the nip pressure altering means and the cutter by setting the nip pressure applied by the paired rollers at a first nip pressure, rotating the paired rollers in respective predetermined directions so that the package is forwarded along the predetermined transferring path, terminating rotation of the paired rollers when the rear edge of the package comes between the paired rollers, making a slit on the package, setting the nip pressure applied by the paired roller at a second nip pressure which is larger than the first nip pressure, and rotating the paired roller in the directions opposite to the predetermined directions so that only the wrapping sheet separated from the solid object is transferred back by the paired rollers.
The term xe2x80x9cthe front edge of the packagexe2x80x9d refers to the edge at the head of the package while being forwarded along the transferring path by the paired rollers rotating in the above predetermined directions. On the other hand, the term xe2x80x9cthe rear edge of the packagexe2x80x9d refers to the edge at the tail of the package while being forwarded by the paired rollers rotating in the above predetermined directions.
The term xe2x80x9ca first nip pressurexe2x80x9d refers to a relatively low nip pressure enabling the paired rollers to run on the portion of the package where the solid object resides. On the other hand, the term xe2x80x9ca second nip pressurexe2x80x9d refers to a relatively high nip pressure preventing the paired rollers from running on the portion of the package where the solid object resides therein. That is to say, the solid object in the package is squeezed back within the unsealed space in the package when the second nip pressure is applied by the paired rollers.
When using the above unwrapping apparatus according to the second aspect of the present invention, the rotation of the paired rollers is terminated when the rear edge of the package comes between the paired rollers after the paired rollers under the first nip pressure have run on the portion of the package where the solid object resides. Then, the paired rollers, which are now set at the second nip pressure, are rotated in the opposite directions after the slit is formed on the package. Accordingly, as the solid object within the package cannot be held between the paired rollers and thus cannot be transferred backward, only the wrapping sheet is transferred back to the area in front of the paired rollers. Therefore, the solid object within the package is gradually squeezed out from the slit formed on the package, and the solid object is separated from the wrapping sheet. That is to say, the unwrapping apparatus according to the second aspect of the present invention automatically unwraps the package to separate the solid object therein from the wrapping sheet. In addition, as the wrapping sheet separated from the solid object is pressed between the paired rollers while being transferred backward, the bulk of the removed wrapping sheet is reduced to facilitate handling thereof.
It is desirable that the unwrapping apparatus according to the second aspect of the present invention further comprises shift detecting means for recognizing that the solid object has been sufficiently squeezed back to the rear end of the unsealed space in the package; wherein the controlling means further controls operations of the paired rollers, the nip pressure altering means and the shift detecting means by setting the nip pressure applied by the paired rollers at a third nip pressure which is larger than the first nip pressure before setting the nip pressure at the first nip pressure, rotating the paired rollers in the predetermined directions so that the package is forwarded along the predetermined transferring path, and changing the nip pressure applied by the paired rollers to the first nip pressure when the shift detecting means recognizes that the solid object has been sufficiently squeezed back to the rear end of the unsealed space in the package.
The term xe2x80x9ca third nip pressurexe2x80x9d refers to another relatively high nip pressure preventing the paired rollers from running on the portion of the package where the solid object resides. That is to say, the solid object in the package is squeezed back within the unsealed space in the package when the third nip pressure is applied by the paired rollers. The third nip pressure may be the same pressure as the second nip pressure described above.
In the above case where the unwrapping apparatus further comprises the shift detecting means, the paired rollers first forward the package with the third nip pressure which is larger than the first nip pressure. Accordingly, the solid object is squeezed back by the paired rollers within the unsealed space in the package. Once the shift detecting means recognizes that the solid object has been sufficiently squeezed back to the rear end of the unsealed space, the nip pressure applied by the paired rollers will be changed to the first nip pressure which enables the paired rollers to run on the portion of the package where the solid object resides. The forwarding operation of the paired rollers will be terminated when the rear edge of the package comes between the paired rollers. As the solid object has already been squeezed back to the rear end of the unsealed space, a relatively wide cut allowance can be obtained at the front edge of the package. Therefore, the unwrapping apparatus with the shift detecting means realizes a safer and easier cutting operation.
In addition, it is desirable that the unwrapping apparatus according to the second aspect of the present invention further comprises a squeezing member located in front of the paired rollers along the transferring path in such a manner that the squeezing member can be freely inserted into and retracted from the transferring path; wherein the controlling means further controls an operation of the squeezing member by inserting the squeezing member into the transferring path before forwarding the package under the third nip pressure, and retracting the squeezing member from the transferring path when the shift detecting means recognizes that the solid object has been sufficiently squeezed back to the rear end of the unsealed space of the package. In this case, the dedicated squeezing member located in front of the paired rollers squeezes the solid object backward as the paired rollers forward the package with the third nip pressure. Therefore, the solid object can be reliably squeezed back to the rear end of the unsealed space to form a wide cut allowance at the front edge of the package, even if the solid object is relatively thin, by using a suitably structured squeezing member.
Further, it is desirable that the unwrapping apparatus according to the second aspect of the present invention further comprises edge detecting means for detecting the front edge of the package located in front of the paired rollers along the transferring path; wherein the controlling means further controls operations of the paired rollers by causing the paired rollers to begin the rotation in the predetermined directions after the front edge of the package is detected by the edge detecting means. Such a configuration is effective in reducing power consumption, as the rotation of the paired rollers is activated after the edge detecting means detects the front edge of the package and is suspended during the cutting operation.
In addition, it is desirable that the unwrapping apparatus according to the second aspect of the present invention further comprises an object cartridge which is used for housing the solid object after being separated from the wrapping sheet and which is located behind the paired rollers along the transferring path. Such an object cartridge facilitates handling of the unwrapped solid object. The use of the object cartridge is especially effective when the solid object is a slide for chemical analysis as described above, as a plurality of unwrapped slides housed in a desired order in the object cartridge may be mounted directly on a biochemical analyzer.
Further, it is desirable that the unwrapping apparatus according to the second aspect of the present invention further comprises a disposal bin which is used for temporarily storing the wrapping sheet removed from the solid object and which is located in front of the paired rollers along the transferring path. Such a disposal bin facilitates handling of the removed wrapping sheet to be discarded.
In addition, it is desirable that the slit formed by the cutter is shorter than the entire width of the package. Such a form of the slit, which prevents the wrapping sheet from splitting in two, also facilitates handling of the removed wrapping sheet to be discarded.